Resolve "Commits graph has overlapping text on mobile"

Apply responsive design for labels on Commits and Continuous Integration graphs.

What does this MR do?

Make the labels on Commits and Continuous Integration graphs smaller for mobile devices.

Are there points in the code the reviewer needs to double check?

Graphs should not break at any screen size.

Why was this MR needed?

Labels overlaps each other on mobile devices.

What are the relevant issue numbers?

Fixes #18846 (closed) (but also fixes a similar bug on Continuous Integration graph).

Screenshots (if relevant)

Before:

After:

Does this MR meet the acceptance criteria?

• [ ] CHANGELOG entry added
• [ ] Documentation created/updated
• [ ] API support added
• Tests
  • [ ] Added for this feature/bug
  • All builds are passing
• Conform by the style guides
• Branch has no merge conflicts with master (if you do - rebase it please)
• Squashed related commits together

cc: @jschatz1